Physical Review Letters

(Phys.org)—Any number can, in theory, be written as the product of prime numbers. For small numbers, this is easy (for example, the prime factors of 12 are 2, 2, and 3), but for large numbers, prime factorization becomes ...

Inspired by the way people move at heavy metal concerts, an international team of researchers from Uppsala University and Harvard University have learned how to spot danger zones in mass gatherings before disaster strikes.

Anyone who has tried to lead a group of tourists through a busy city knows the problem. How do you keep the group together when they are constantly jostled, held up and distracted by the hubbub around them?

In an electron microscope, electrons are emitted by pointy metal tips, so they can be steered and controlled with high precision. Recently, such metal tips have also been used as high precision electron sources for generating ...

High above the surface, Earth's magnetic field constantly deflects incoming supersonic particles from the sun. These particles are disturbed in regions just outside of Earth's magnetic field - and some are reflected into ...

Nature is full of parasites—organisms that flourish and proliferate at the expense of another species. Surprisingly, these same competing roles of parasite and host can be found in the microscopic molecular world of the ...